The present application is directed to an anaerobic upflow batch reactor for the removal of contaminants, especially organic contaminants, from waste water utilizing a processing method wherein the waste water being treated flows in a plug flow configuration from near the bottom of the reactor to near the top of the fluid within the reactor.
Historically, numerous systems have been developed by waste water engineers for the treatment of waste water to remove impurities therefrom. Such systems have included continuous flow type reactors as well as batch type reactors. Systems have also included aerobic, anaerobic and combinations of aerobic and anaerobic treatments of the waste water. The present invention is directed to a modification of anaerobic batch systems in order to produce special processing characteristics within the system.
In particular, upflow batch reactor systems have been produced in the past for treating the waste water and an example of such a system is shown in the Dague U.S. Pat. No. 5,185,079. Batch reactors have certain advantages over continuous flow reactors in that the material to be treated can be positively maintained within the batch reactor until the process is complete whereas in continuous flow reactors there is a possibility of incomplete reaction before the waste water exits the process.
The inventors of the present invention have found that careful control of certain parameters of a batch system substantially enhances the ability of the batch reactor to complete its task. In particular, they have discovered that, if the flow through the reactor can be maintained as a substantially true plug flow from near the bottom of the reactor to near the top of the liquid, a reaction gradient can be produced that has special advantages to the operation to the system. However, these advantages are mostly lost if flow in the reactor is not plug flow throughout. This is true even where the flow starts as plug flow, but does not raise substantially vertically through the reactor, such as where there is a side takeoff and a substantial amount of the flow is horizontal or diagonal relative to the reactor.
In particular, if the concentration of the biomass and food substrate which feeds the biomass within the waste water can be carefully controlled to move through the reactor in a movement that is designed to pass from the bottom of the reactor to near the top of the liquid in a mostly vertical direction (that is the individual molecules have a mainly vertical vector associated therewith and without substantial mixing, the advantageous growth of particular types of biomass in particular areas of the reactor can be enhanced and the biomass that might otherwise be entrained with the fully treated liquid, as the liquid leaves the reactor, can be substantially reduced.
The prior art upflow anaerobic batch reactors of the type shown in the above noted Dague patent have failed to take advantage of such a system and, in particular, have typically withdrawn fluid from the reactor from the side or otherwise unevenly such that movement through the reactor is not substantially up and down, but rather has a substantial sideways component. Withdrawal from the side, as in Dague and other prior art references, causes mixing which also defeats the goals of the process of the present application.